How can I code this script better? Search & extract values from an array in PHP

I managed to write the following function which took me all afternoon. I used various sources and managed to cobble something together. I'm a newbie. It works, but I'm sure it can be coded better and more efficiently. If anybody has any ideas..

Here is my array:

Array
(
    [0] => Array
        (
            [database] => oneclick_themes
            [disk_usage] => 16384
            [users] => Array
                (
                    [0] => oneclick_themes
                )

        )

    [1] => Array
        (
            [database] => oneclick_wp1
            [disk_usage] => 123230
            [users] => Array
                (
                    [0] => oneclick_wp1
                )

        )

    [2] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp10
                )

            [database] => oneclick_wp10
            [disk_usage] => 123230
        )

    [3] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp11
                )

            [disk_usage] => 123222
            [database] => oneclick_wp11
        )

    [4] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp12
                )

            [disk_usage] => 123230
            [database] => oneclick_wp12
        )

    [5] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp13
                )

            [disk_usage] => 123222
            [database] => oneclick_wp13
        )

    [6] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp14
                )

            [database] => oneclick_wp14
            [disk_usage] => 123222
        )

    [7] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp2
                )

            [disk_usage] => 123226
            [database] => oneclick_wp2
        )

    [8] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp3
                )

            [disk_usage] => 0
            [database] => oneclick_wp3
        )

    [9] => Array
        (
            [database] => oneclick_wp4
            [disk_usage] => 123230
            [users] => Array
                (
                    [0] => oneclick_wp4
                )

        )

    [10] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp5
                )

            [database] => oneclick_wp5
            [disk_usage] => 0
        )

    [11] => Array
        (
            [users] => Array
                (
                    [0] => oneclick_wp6
                )

            [database] => oneclick_wp6
            [disk_usage] => 0
        )

    [12] => Array
        (
            [disk_usage] => 123222
            [database] => oneclick_wp7
            [users] => Array
                (
                    [0] => oneclick_wp7
                )

        )

    [13] => Array
        (
            [disk_usage] => 123222
            [database] => oneclick_wp8
            [users] => Array
                (
                    [0] => oneclick_wp8
                )

        )

    [14] => Array
        (
            [database] => oneclick_wp9
            [disk_usage] => 0
            [users] => Array
                (
                    [0] => oneclick_wp9
                )

        )

)

This is my PHP code:

$array = array();
function search_array($array, $val) {
    $ArrIterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($array)); 
    foreach($ArrIterator as $id => $sub) {
      $childArray = $ArrIterator->getSubIterator();
      if(strstr(strtolower($sub), strtolower($val))) {
        $childArray = iterator_to_array($childArray);
        $result[] = $childArray['database'];
      }
    }  
    return $result;
}
$results = array_filter( search_array( $array, '_wp') );
foreach( $results as $key=> $value ) {
  $results[$key] = str_replace( $wp_db_prefix . "wp","", $value);
};
$wp_next_db_name = max($results) + 1;

Here is what it does.

It searches a multi-dimensional array which MYSQL DB info for the "_wp" string within the values.

Then it filters out the user account prefix "oneclick_" with prefix "wp" which leaves me with integers.

Then I find the highest value (max) and increment by 1.

The purpose is for a cPanel plugin to create incremental DB names.